Despite the prevalence of music sold on compact discs and MP3 files, records are still regarded by some audiophiles as producing the best sound quality when playing the music stored thereon. Record players rely on a tone arm having a needle or stylus that follows a spiral, modulated groove defined within the surface of the record. The stylus is operatively connected to an electromagnetic pickup, which converts the stylus movements into an electrical signal. This electrical signal is amplified and then supplied to a speaker. While CD's and MP3 files store the music digitally, records store the music in an analog format.
Unlike CD's or MP3 files, users of manual record players must manually move the record player's tone arm to the starting location of the desired song on the record. Various automatic record players automatically detect the locations between songs, and position the tonearm accordingly. However, the additional hardware needed for automatic tone arm movement increases the weight of the tonearm, which impacts the sensitivity of the tonearm. While some manual record players can track to 0.5 grams, the best automatic record players can only track to 1.5 grams, thus reducing the sound quality of the record player.
An example of a presently available automated record player system is U.S. Pat. No. 4,398,278, which discloses a record player program selector. The programs on the record are separated by inter-program gaps. The reflectivity of the surface of the record at locations where sound grooves are located is different from the reflectivity of the surface of the inter-program gaps. A photo sensor mounted on the housing of the turntable is utilized to determine the location of each inter-program gap. The location of the lead-in groove of the record can also be detected using the light sensor. The desired track is selected using a selector switch, and the inter-program gap located before the desired program is set as the location to which the tone arm should be moved. A light source and light sensor on the tonearm is used in connection with an optically detectable radial scale to determine the position of the tonearm as it moves across the surface of the record. The tonearm position sensor is compared to the inter-program gap signal to determine whether the tonearm is in the location of the selected program. Alternatively, the radial scale can be spaced magnetic elements that are sensed by a magnetic sensor on the tonearm. The user may select the desired track using a selector switch.
DE 2839801 discloses a record player tone arm vertical and rotary motion control. A follower and lift platform coaxial with the tone arm and driven by the player motor is used. The device can be controlled remotely.
JP 62257601 discloses a remote control for a record player, allowing the tonearm to be elevated and then rotated to a desired position on a record.
JP 58215701 discloses a device for engaging the tonearm and a lifting mechanism. The tonearm is free to move horizontally when the lifting mechanism is disengaged.
JP 58102303 discloses an elevator for a tonearm. The elevator includes an auxiliary arm on the tonearm, and a receiving plate for contacting the auxiliary arm. The receiving plate is part of a piston rod.
U.S. Pat. No. 4,694,449 discloses a record player with a pickup arm lift rod. The lifting device includes a horizontal arm support formed integrally with a vertical lifting rod. The lifting rod fits within a square tubular guide element that is integrally formed with the deck. The lower end of the lift rod engages an actuating member having a pair of support surfaces at different levels, connected by a ramped surface. Sliding the actuating member thereby raises and lowers the lift rod. An angled compression spring both biases the lift rod downward, and pushes the lift rod against a pair of the guide surfaces. Silicon lubricant is maintained between the lift arm and the guide surfaces by capillary action.
U.S. Pat. No. 4,437,180 discloses an apparatus for controlling a pickup arm in a record or video disc player. An optical detector is located at the foremost end of the pickup arm for detecting a non-recorded groove portion. The tonearm moves until a selected non-recorded groove portion is reached, and then the tonearm is lowered. The light sensor includes an LED and a phototransistor. A pickup arm position detecting section includes a photo coupler having a light emitting diode and a phototransistor facing each other, with a shutter plate. A counter is used to track the number of the song on which the stylus is positioned. A second counter, which is set by the number of depressions of the play button, is used to select the desired song. A pickup arm lifter controlling circuit is used to raise the pickup arm when the stop button is depressed, and to lower the pickup arm when the pickup arm is in a desired location. A pickup arm horizontal controlling circuit moves the pickup arm towards the center of the record, unless the stop button is depressed, in which case the pickup arm is moved outward. Manual control of the pickup arm is also provided. When operated in automatic mode, the pickup arm is moved inward until the count value equals the designated number of the piece selected. At this point, the pickup arm will overswing the desired location, but then be brought back by the reversing controlling section for a tiny distance, and then positioned accurately above the non-recorded portion of the groove located immediately before the designated number of piece of music. The pickup arm is then lowered.
U.S. Pat. No. 4,301,526 discloses a tonearm control system. The tonearm is moved along a worm gear. A shutter attached to the worm gear is placed between a light source and a light sensor, so that the light pulses detected by the light sensor can be used to indicate the absolute position of the tonearm. A sensor on the on the tonearm detects gaps between grooved sections on a record. The user may elect to play songs on the record in a given order. The tonearm moves to the location of the song from its start position by counting spaces on the record between grooved song sections, remembering each tone arm position in which a section between songs is detected.
U.S. Pat. No. 4,114,893 discloses gramophone equipment incorporating a means of permitting a user to play selected tracks. A photoelectric sensor located at the end of the tonearm is used to detect bands between record tracks. A counter is used to count the detected bands. Track selections may be input and stored into memory. Control circuitry is provided for lifting the tonearm as well as for driving the tonearm laterally to the desired location.
U.S. Pat. No. 3,937,903 discloses a soundtrack selector system for phonograph record players. The stylus pickup arm includes an infrared light emitter and light sensor, directing light to the face of the phonograph record and receiving reflected light. Bands between recorded songs are thereby detected. An optical encoder is used to detect the peripheral position of the pickup arm with respect to the record. The pickup arm is moved using a pulse motor that is geared down sufficiently to give the necessary incremental resolution. The use of the encoder's output signal to supplement the detector signal in the pickup arm eliminates the elaborate optical detection techniques utilized by other systems. The user may select the specific bands of the record to be played. The system can be extended to multiple records, tracking not only the band being played but also the record within the group of records that is being played.
U.S. Pat. No. 3,727,922 discloses a tonearm lifting device for an automatic record player. The lifting mechanism includes a cylinder with a piston slidably mounted therein. A lifting rod is secured within the piston, and a lifting plate for the tonearm is mounted on the lifting rod. An eccentric cam is used to move the piston upward.
JP 60131602 discloses the use of a remote control solenoid for raising and lowering the tonearm of a record player.
U.S. Pat. No. 4,226,425 discloses a nonrecorded section detection scanner mounted on a sensor arm. The sensor arm is mounted to a rotating shaft having a drive mechanism and a slit plate fixed to the shaft. The slit plate is used to detect to the rotation of the shaft so that the location of nonrecorded sections between adjacent tracts of a record can be located. The tonearm includes a drive shaft having another slit plate to detect the address of the pickup cartridge. Each of the slip plates includes a slit plate sensor having a light emitting diode on one side of the slit plate, and a photosensitive transistor on the other side of the slit plate. A counter is connected to each of the sensors to count the pulse signals derived therefrom.
Accordingly, there is a need for an automatic record player having the tonearm sensitivity of a manual record player. There is a further need for a means of converting a manual record player to an automatic record player without affecting the sensitivity of the tonearm. Additionally, there is a need for a manual to automatic record player conversion that minimizes the amount of weight added to the tone arm.